CHAPTER 2.1 BOHR'S ATOMIC MODEL

Energy is emitted or absorbed by an electron when it make a transition form one energy state to another.

• First postulate

• Second postulate

• Third postulate

• Forth postulate

Which of the formula is used for the question below?

Calculation the energy of an electron at energy level n=3.

• $\Delta E\ =\ R\ \left[\frac{1}{n_i^{\ \ 2}}\ -\ \frac{1}{n_f^{\ \ 2}}\right]$

• $E_n=-R_H\ \left[\frac{1}{n^2}\right]$

• $\Delta E=hv$

• $\frac{1}{\lambda}=R_{H\ }\left[\frac{1}{n_1^{\ \ 2\ }}-\frac{1}{n_2^{\ \ 2}}\right]\ ,\ \ \ n_2\ >n_1\ ,\ \lambda>0$

Choose the MOST suitable formula to solve the question below.

Determine the wavelength of a photon when it was excited from n=2 to n=5.

• $\Delta E\ =hv$

• $\Delta E\ =R_{H\ }\left[\frac{1}{n_{i\ }^{\ \ 2}}\ -\frac{1}{n_f^{\ \ \ 2}}\right]$

• $\frac{1}{\lambda}=R_{H\ }\left[\frac{1}{n_1^{\ \ 2}}-\frac{1}{n_2^{\ \ 2}}\right]\ \ ,\ \ n_{2\ }>n_{1\ \ },\ \lambda>0$

• $E_{n_{\ }}=\ -R_H\left[\frac{1}{n^2}\right]$

An emission line spectrum is formed when an electron make a transition from n=5 to n=3.

State the series of the above transition.

• Lyman

• Balmer

• Paschen

• Brackett

• Pfund

An emission line spectrum shows red, green, blue and purple line.

In which series you will see these colour lines?

• Lyman

• Balmer

• Paschen

• Brackett

• Pfund

What is the transition of a photon for the third line in Lyman series?

• n=5 to n =2

• n=6 to n=3

• n=3 to n=1

• n=4 to n=1